chown

Changes the owner (and group) of a list of files. The first two
elements of the list must be the numeric uid and gid, in that
order. A value of -1 in either position is interpreted by most
systems to leave that value unchanged. Returns the number of files
successfully changed.

On systems that support fchown(2), you may pass filehandles among the
files. On systems that don't support fchown(2), passing filehandles raises
an exception. Filehandles must be passed as globs or glob references to be
recognized; barewords are considered filenames.

On most systems, you are not allowed to change the ownership of the
file unless you're the superuser, although you should be able to change
the group to any of your secondary groups. On insecure systems, these
restrictions may be relaxed, but this is not a portable assumption.
On POSIX systems, you can detect this condition this way: